Simulation study of separating oxygen from air by pressure swing adsorption process with semicylindrical adsorber

Abstract

This study utilizes zeolite 5A to separate oxygen from air in order to compare the performance of semicylindrical adsorber with that of traditional cylindrical adsorber for pressure swing adsorption by simulation. Semicylindrical adsorber can have better heat compensation during adsorption and desorption steps, which increases the oxygen purity of product in Skarstrom cycle operation. The air composition is simplified to 21% oxygen, 1% argon and 78% nitrogen. The extended Langmuir isotherm model is used to describe adsorption isotherms of gas components. The linear driving force model is used to describe the mass transfer resistance between gas and solid phase. Furthermore, the simulation program is verified with experimental data. The results show the reliability of the program and parameters. Then, we build a PSA process with semicylindrical adsorbers under appropriate operating conditions and compared it with a PSA process with traditional cylindrical adsorbers. From the results of discussing the operating variables, heat compensation of semicylindrical adsorber does increase oxygen purity for oxygen separation from air, once the adsorber changed from cylindrical one into semicylindrical one. The benefit of heat compensation is more obvious for larger adsorber, higher operating and surrounding temperature, and lower feed pressure in the range of this study.